Profilometry of metal additive manufactured rough surfaces by applying Focus Variation Microscopy

Fig.1: (left) Schematic drawing of the focus variation microscopy, (right) photo of the focus variation microscope system.

In this project, a focus variation microscope (FVM), used to measure areal topography and areal field texture parameters of metal additive manufactured rough surfaces, is constructed. A ring light in combination with coaxial illumination is studied to provide an all-round lighting due to the high degree of irregularity of surfaces, especially the occurrence of steep slopes. The reconstructed surface suffers from local errors introduced by certain range of defocused images captured during depth scanning. An algorithm based on autocorrelation functions of particular images is developed to eliminate these errors.

Fig. 2: (left) (a) Image captured by using only coaxial illumination, (b) image captured by using only ring light illumination, (c) image captured by using coaxial and ring light illumination, (right) one example of reconstructed surface sections from a work piece manufactured by metal additive method.

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M.Sc. Xin Xu